/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 * 
 *      http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.apache.catalina.mbeans;

import org.apache.catalina.*;
import org.apache.juli.logging.Log;
import org.apache.juli.logging.LogFactory;
import org.apache.tomcat.util.modeler.Registry;

import javax.naming.*;
import javax.naming.Context;
import java.util.Iterator;

/**
 * Implementation of <code>LifecycleListener</code> that instantiates the
 * set of MBeans associated with global JNDI resources that are subject to
 * management.
 *
 * @author Craig R. McClanahan
 * @since 4.1
 */
public class GlobalResourcesLifecycleListener
		implements LifecycleListener {
	private static final Log log = LogFactory.getLog(GlobalResourcesLifecycleListener.class);

	// ----------------------------------------------------- Instance Variables
	/**
	 * The configuration information registry for our managed beans.
	 */
	protected static Registry registry = MBeanUtils.createRegistry();
	/**
	 * The owning Catalina component that we are attached to.
	 */
	protected Lifecycle component = null;


	// ---------------------------------------------- LifecycleListener Methods

	/**
	 * Primary entry point for startup and shutdown events.
	 *
	 * @param event The event that has occurred
	 */
	@Override
	public void lifecycleEvent(LifecycleEvent event) {

		if (Lifecycle.START_EVENT.equals(event.getType())) {
			component = event.getLifecycle();
			createMBeans();
		} else if (Lifecycle.STOP_EVENT.equals(event.getType())) {
			destroyMBeans();
			component = null;
		}

	}


	// ------------------------------------------------------ Protected Methods

	/**
	 * Create the MBeans for the interesting global JNDI resources.
	 */
	protected void createMBeans() {

		// Look up our global naming context
		Context context = null;
		try {
			context = (Context) (new InitialContext()).lookup("java:/");
		} catch (NamingException e) {
			log.error("No global naming context defined for server");
			return;
		}

		// Recurse through the defined global JNDI resources context
		try {
			createMBeans("", context);
		} catch (NamingException e) {
			log.error("Exception processing Global JNDI Resources", e);
		}

	}

	/**
	 * Create the MBeans for the interesting global JNDI resources in
	 * the specified naming context.
	 *
	 * @param prefix  Prefix for complete object name paths
	 * @param context Context to be scanned
	 * @throws NamingException if a JNDI exception occurs
	 */
	protected void createMBeans(String prefix, Context context)
			throws NamingException {

		if (log.isDebugEnabled()) {
			log.debug("Creating MBeans for Global JNDI Resources in Context '" +
					prefix + "'");
		}

		try {
			NamingEnumeration<Binding> bindings = context.listBindings("");
			while (bindings.hasMore()) {
				Binding binding = bindings.next();
				String name = prefix + binding.getName();
				Object value = context.lookup(binding.getName());
				if (log.isDebugEnabled()) {
					log.debug("Checking resource " + name);
				}
				if (value instanceof Context) {
					createMBeans(name + "/", (Context) value);
				} else if (value instanceof UserDatabase) {
					try {
						createMBeans(name, (UserDatabase) value);
					} catch (Exception e) {
						log.error("Exception creating UserDatabase MBeans for " + name,
								e);
					}
				}
			}
		} catch (RuntimeException ex) {
			log.error("RuntimeException " + ex);
		} catch (OperationNotSupportedException ex) {
			log.error("Operation not supported " + ex);
		}

	}

	/**
	 * Create the MBeans for the specified UserDatabase and its contents.
	 *
	 * @param name     Complete resource name of this UserDatabase
	 * @param database The UserDatabase to be processed
	 * @throws Exception if an exception occurs while creating MBeans
	 */
	protected void createMBeans(String name, UserDatabase database)
			throws Exception {

		// Create the MBean for the UserDatabase itself
		if (log.isDebugEnabled()) {
			log.debug("Creating UserDatabase MBeans for resource " + name);
			log.debug("Database=" + database);
		}
		try {
			MBeanUtils.createMBean(database);
		} catch (Exception e) {
			throw new IllegalArgumentException(
					"Cannot create UserDatabase MBean for resource " + name, e);
		}

		// Create the MBeans for each defined Role
		Iterator<Role> roles = database.getRoles();
		while (roles.hasNext()) {
			Role role = roles.next();
			if (log.isDebugEnabled()) {
				log.debug("  Creating Role MBean for role " + role);
			}
			try {
				MBeanUtils.createMBean(role);
			} catch (Exception e) {
				throw new IllegalArgumentException(
						"Cannot create Role MBean for role " + role, e);
			}
		}

		// Create the MBeans for each defined Group
		Iterator<Group> groups = database.getGroups();
		while (groups.hasNext()) {
			Group group = groups.next();
			if (log.isDebugEnabled()) {
				log.debug("  Creating Group MBean for group " + group);
			}
			try {
				MBeanUtils.createMBean(group);
			} catch (Exception e) {
				throw new IllegalArgumentException(
						"Cannot create Group MBean for group " + group, e);
			}
		}

		// Create the MBeans for each defined User
		Iterator<User> users = database.getUsers();
		while (users.hasNext()) {
			User user = users.next();
			if (log.isDebugEnabled()) {
				log.debug("  Creating User MBean for user " + user);
			}
			try {
				MBeanUtils.createMBean(user);
			} catch (Exception e) {
				throw new IllegalArgumentException(
						"Cannot create User MBean for user " + user, e);
			}
		}

	}

	/**
	 * Destroy the MBeans for the interesting global JNDI resources.
	 */
	protected void destroyMBeans() {

		if (log.isDebugEnabled()) {
			log.debug("Destroying MBeans for Global JNDI Resources");
		}

	}

}
